package BankTest;

/**
 * @author 李泽伟
 */
public class BankTest {
    public static void main(String[] args) {

    }
}
class Bank{
    private Bank(){}
    private static Bank instance = null;
    public static Bank getInstance(){
        if (instance == null) {
            synchronized (Bank.class){
                if (instance == null) {
                    instance = new Bank();
                }
            }
        }
        return instance;
    }
}
